The table below has information regarding and the nature (acidic/basic) of four different solutions. Which one of the options in the table is correct?
Option Solution Colour of pH paper Approximate pH value Nature of solution (a) Lemon juice Orange 3 Basic (b) Milk of magnesia Blue 10 Basic (c) Gastric juice Red 6 Acidic (d) Pure water Yellow 7 Neutral
The table below has information regarding and the nature (acidic/basic) of four different solutions. Which one of the options in the table is correct?
| Option | Solution | Colour of pH paper | Approximate pH value | Nature of solution |
|---|---|---|---|---|
| (a) | Lemon juice | Orange | 3 | Basic |
| (b) | Milk of magnesia | Blue | 10 | Basic |
| (c) | Gastric juice | Red | 6 | Acidic |
| (d) | Pure water | Yellow | 7 | Neutral |
Options
Official answer
The correct option is (b). Milk of magnesia is basic in nature with an approximate pH value of 10, and it turns pH paper blue.
Marking scheme
- 1.Identification of the correct option (b) (1 mark)
Hint
Think about the pH of common household antacids like Milk of Magnesia, which is used to neutralize excess stomach acid.
Quick oral answer
Milk of magnesia has a pH of approximately 10 and is basic in nature. It turns pH paper blue.
Common mistakes
- 1.Confusing the color of neutral pH paper (green) with yellow.
- 2.Misremembering the highly acidic nature of gastric juice (pH ~1.2) as weakly acidic (pH ~6).
Analysis and explanation
Let us analyze each option based on the NCERT text and pH values:
- Option (a) is incorrect: Lemon juice is highly acidic (approximate pH of 2.2), not basic.
- Option (b) is correct: Milk of magnesia (magnesium hydroxide) is a mild base with a pH of approximately 10. It turns universal indicator/pH paper blue, confirming its basic nature.
- Option (c) is incorrect: Gastric juice is highly acidic with a pH of about 1.2, not 6.
- Option (d) is incorrect: Pure water is neutral with a pH of 7, but it turns pH paper green, not yellow.
Interesting facts
Milk of magnesia is a suspension of magnesium hydroxide in water, commonly used as an antacid to relieve indigestion and heartburn by neutralizing excess stomach acid.
Question details
Q4 of 39 questions
- Board
- CBSE
- Class
- Class 10
- Subject
- Science
- Year
- 2023
- Section
- Section A
- Marks
- 1
- Type
- MCQ
- Chapter
- Acids, Bases and Salts
- Topic
- pH Scale and Indicators
- Bloom's level
- Remembering
- Syllabus topic
- pH scale, importance of pH in everyday life.
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Frequently asked questions
How many marks does this question carry in CBSE Class 10 Science 2023?
This question carries 1 mark in the CBSE Class 10 Science 2023 examination.
Which chapter does this question come from in Science?
This question is from the chapter "Acids, Bases and Salts" in the CBSE Class 10 Science syllabus.
What topic does this question cover in Science?
This question covers the topic "pH Scale and Indicators" from CBSE Class 10 Science.
What type of question is this in the CBSE Class 10 Science 2023 paper?
This is a MCQ question from Section A in the CBSE Class 10 Science 2023 paper.